Textured glass layers in electronic devices

Abstract

An electronic device may have a housing surrounding an interior in which electrical components are mounted. A display may be mounted to housing structures in the device. The housing may have a rear wall. The display cover layer and rear wall of the housing may be formed from transparent glass layers. Coatings may be formed on inwardly facing surfaces of the transparent glass layers. A coating on a transparent glass layer may be formed from a thin-film interference filter having a stack of dielectric layers. The coating may include an ink layer on the thin-film interference filter. The transparent glass layers may have one or more textured surfaces that allow light at high angles to enter the transparent layers and reflect off the coatings at high angles, thereby adjusting optical properties of the coatings.

What is claimed is: 
     
       1. An electronic device having opposing front and rear faces and an interior, the electronic device comprising:
 a display on the front face; 
 a transparent layer that forms a housing wall on the rear face, wherein the transparent layer has an inner surface facing the interior and an opposing outer surface with surface texture; and 
 a coating on the inner surface comprising a thin-film interference filter, wherein the coating is neutral at on-axis viewing angles and non-neutral at off-axis viewing angles. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the thin-film interference filter is a coating layer on the inner surface of the transparent layer. 
     
     
       3. The electronic device defined in  claim 1  wherein the coating further comprises a buffer layer on the inner surface of the transparent layer and wherein the thin-film interference filter is on the buffer layer. 
     
     
       4. The electronic device defined in  claim 1  wherein the thin-film interference filter is formed on a polymer film and attached to the transparent layer. 
     
     
       5. The electronic device defined in  claim 1  wherein the surface texture is formed from protrusions selected from the group consisting of: semi-spherical bumps and semi-cylindrical bumps. 
     
     
       6. The electronic device defined in  claim 1  wherein the surface texture comprises randomly distributed protrusions and recesses on the outer surface of the transparent layer. 
     
     
       7. The electronic device defined in  claim 1  wherein the on-axis neutral coating exhibits first a and b color coordinates in LAB color space, and wherein a root sum squared of the first a and b color coordinates is less than two in magnitude at a viewing angle of 0°. 
     
     
       8. The electronic device defined in  claim 7  wherein the off-axis non-neutral coating exhibits second a and b color coordinates in LAB color space, and wherein a root sum squared of the second a and b color coordinates is greater than three in magnitude at a viewing angle of 80°. 
     
     
       9. The electronic device defined in  claim 8  wherein the thin-film interference filter has a reflectivity of at least 80% from 400 nm to 700 nm. 
     
     
       10. The electronic device defined in  claim 8  wherein the thin-film interference filter has an L luminance coordinate in LAB color space that changes less than 25% when viewed at viewing angles between 0° and 75°. 
     
     
       11. An electronic device having an interior and an exterior, the electronic device comprising:
 a housing having a rear glass layer that has a textured surface that faces the exterior and an inner surface that faces the interior; and 
 a coating on the inner surface, wherein the coating comprises a thin-film interference filter and wherein the coating is neutral when viewed on-axis and non-neutral when viewed off-axis. 
 
     
     
       12. The electronic device defined in  claim 11  wherein the thin-film interference filter is a band stop filter with a stop band at infrared wavelengths when viewed on-axis. 
     
     
       13. The electronic device defined in  claim 12  wherein the stop band is at visible wavelengths when viewed off-axis. 
     
     
       14. The electronic device defined in  claim 11  wherein the textured surface is a first textured surface and is a first distance from the inner surface of the rear glass layer, and wherein the rear glass layer comprises a second textured surface at a second distance from the inner surface that is different from the first distance and a tapered surface between the first textured surface and the second textured surface.